THE ANATOMY OF THE HORSE 
51 
In starting at the head to trace the blood back to the 
heart, we find it carried from the head by tvy^o very important 
vessels called the jugular veins ; these are important because 
it is from these veins that the animal is bled. The veins 
which run up the inside of the front leg, carrying the blood 
back from the leg, unite with the jugular veins, forming what 
is known as anterior vena cava, which empties into the right 
auricle of the heart. In tracing the blood back from the hind 
leg, a large vein is found on the inside of the leg, passing up 
under the hip, where it unites with the veins of the hip region, 
forming what is known as the posterior vena cava. As it 
passes forward it takes in veins from the various organs such 
as the stomach, liver, kidneys, spleen, and small bowels, and 
finally empties into the right auricle of the heart. This is the 
complete circulation of the blood. 
IV. — HOW TO TELL WHEN AN ARTERY IS CUT. 
There are two important points in which arteries differ 
from veins, consequently there are two important differences 
in bleeding from veins and arteries. When an artery is cut 
two characteristics are noticeable, (1) the blood flows in 
spurts or throbs because of their being directly effected by 
each contraction of the heart; (2) the blood is of a much 
brighter color because of being pure and fresh from the 
purif) ing process in the lungs. On the other hand should a 
vein be cut the character of the bleeding is the reverse. The 
blood (1) flows in a comparatively steady stream because of 
the veins' being unaffected by the heart beats, and (2) being 
impure or on its way to the lungs to be purified is of a much 
darker color. Arteries are always found deep-seated and well 
protected with muscles and bone ; as, for instance, the large 
arteries of the legs always pass down on the inside of the 
leg very close to the bone, and on account of this large 
arteries are very rarely injured. 
